If you are just giving the diff to the guy, and he does this professionally. It should only be close to 2 hrs if he is just adding the ARB to the diff(no gear change). If he is doing gears(bearings and seals, total rebuild) as well it would be close to 3.5 to 4 hrs. To pull the diff out and install the diff in the axle with out a rebuild on the axles time is close to 3.5 to 4 hrs as well. If rebuilding the Axle then a typical axle job is any where from 8 to 10 hrs(depends on the flat rate time). Hope this helps you Kevin with your estimate. later Robbie